Method of controlling drainage of wash water remaining in a washing machine

Abstract

Disclosed herein is a method of controlling drainage of wash water remaining in a washing machine. The method includes draining wash water from a tub to an outside of the washing machine, supplying wash water into the washing machine after the draining wash water, and re-draining the wash water to the outside of the washing machine after the supplying wash water.

What is claimed is: 
     
       1. A method of controlling drainage of water from a washing machine, comprising:
 draining contaminated water from a tub of the washing machine using a drain hose; 
 after draining the contaminated water, determining whether any of the contaminated water is at a first preset point in the drain hose; 
 when the contaminated water is at the first preset point in the drain hose, supplying clean water into the washing machine (i) to a second preset point in the drain hose above the first preset point or (ii) for a preset period of time and, after supplying the clean water, draining the clean water from the washing machine; and 
 after draining the clean water, rinsing laundry in the washing machine, 
 wherein the clean water is supplied to the second preset point of the drain hose, 
 wherein a first water level sensor determines whether any of the contaminated water is at the first preset point in the drain hose, and 
 wherein a second water level sensor determines whether any of the contaminated water is at the second preset point in the drain hose. 
 
     
     
       2. The method of  claim 1 , further comprising, before draining first water, washing laundry in the washing machine, resulting in the contaminated water being the tub. 
     
     
       3. The method of  claim 1 , wherein the clean water is supplied for the preset period of time. 
     
     
       4. The method of  claim 3 , wherein the preset period of time is a period of time for the drain hose to be filled with the clean water. 
     
     
       5. The method of  claim 1 , wherein the first water level sensor is at the first preset point in the drain hose. 
     
     
       6. The method of  claim 1 , wherein the second water level sensor is at the second preset point in the drain hose. 
     
     
       7. The method of  claim 6 , wherein the second preset point in the drain hose is at an upper end of the drain hose. 
     
     
       8. The method of  claim 1 , wherein the contaminated water is drained from the drain hose by operating a drain pump. 
     
     
       9. The method of  claim 8 , wherein the clean water is drained from the drain hose by operating the drain pump. 
     
     
       10. The method of  claim 1 , further comprising repeating supplying clean water into the washing machine and draining the clean water from the washing machine when contaminated water is detected in the drain hose. 
     
     
       11. A washing machine, comprising:
 a tub configured to contain contaminated wash water and clean rinse water; 
 a drain hose at a bottom of the tub; 
 a first water level sensor at a first preset point in the drain hose; 
 a second water level sensor at a second preset point in the drain hose above the first preset point; 
 a controller configured to determine whether any contaminated wash water is at the first preset point in the drain hose after the contaminated wash water is drained from the tub, and when the contaminated wash water is at the first preset point in the drain hose, supply clean water into the tub to the second preset point in the drain hose, drain the clean water from the tub, then supply the clean rinse water to the tub; and 
 a drain pump that drains the contaminated wash water, the clean water, and the clean rinse water from the tub. 
 
     
     
       12. The washing machine of  claim 11 , further comprising a cabinet that constitutes an outer appearance of the washing machine, a drum inside the tub to receive laundry, and a door opening and closing an opening on a front side of the cabinet. 
     
     
       13. The washing machine of  claim 11 , further comprising a water supply tube connected to a water source to supply water into the tub.